The present invention relates to a water softening device for softening raw water containing hardness components by ion exchange, and to a method for regeneration control thereof.
As generally known, feedwater lines to heating and cooling apparatuses such as boilers, water heaters, or radiators are connected to devices for removing hardness components contained in feedwater for preventing scaling in the heating and cooling apparatuses, among which an automatic regenerative water softener for removing hardness components with use of ion exchange resin is widely adopted. This type of water softer uses Na+ type ion exchange resin to replace metal cation such as Ca2+ and Mg2+, i.e., hardness components contained in water, with Na+ for removing the hardness components. When the ion exchange resin is replaced with cation and saturated, and thereby exhausted capability of removing the hardness components, the ion exchange resin is reacted with brine for performing regenerating operation for regenerating the capability.
Generally, effective regenerating operation is preferably conducted by detecting a saturation degree of the ion exchange resin, feeding a required minimum amount of regenerative brine according to respective conditions, and performing regeneration control at the proper time in conformity with the saturation degree. As a conventional control method, there is a metered regeneration method, in which in installing the water softener, the hardness of feedwater in the installation site is measured in advance, the quantity of treatable water by a specified amount of the ion exchange resin (i.e., the quantity of water that the ion exchange resin can soften till regenerating operation is put into operation) is calculated based on the measured value, and regenerating operation is carried out when flow volume of feedwater reaches the calculated quantity of treatable water.
In the metered regeneration method, the hardness of feedwater fed to raw water lines is determined by detecting the hardness of feedwater (underground water, tap water, etc.) in advance at the time of installing the water softener, and calculating the quantity of treatable water based on the detected value. However, the hardness of the feedwater, especially in the case of underground water fluctuates by seasonal factors. Therefore, in order to prevent the ion exchange resin from reaching a breakthrough point (hardness leakage), the quantity of treatable water is reduced from the calculated value to be a fail-safe quantity. Eventually, even when the ion exchange resin has a softening ability (so called a remaining ability), regenerating operation may be carried out, which wastes brine for regenerating operation.
In view of the above stated problem, an object of the present invention is to provide a water softening device and a method for regeneration control thereof, in which the hardness of feedwater to be softened is detected with the lapse of time and regeneration timing is controlled based on the detected value.
The present invention has been invented to solve the above-stated problem. An invention according to a first aspect is composed of inlet hardness measurement means for measuring hardness of feedwater to a water softener, treated water quantity measurement means for measuring a flow rate of treated water after passing through the water softener, brine concentration detection means for detecting concentration of brine in regenerating operation, and brine consumption detection means for detecting consumption of brine in regenerating operation.
An invention according to a second aspect is composed of hardness leakage detection means for measuring hardness of treated water after passing through the water softener and detecting hardness leakage.
An invention according to a third aspect is composed of a plurality of water softening devices disposed and connected in parallel with water flowing operation and regenerating operation of each water softening device switchable, the water softening device composed of inlet hardness measurement means for measuring hardness of feedwater to a water softener, treated water quantity measurement means for measuring a flow rate of treated water after passing through the water softener, brine concentration detection means for detecting concentration of brine in regenerating operation, and brine consumption detection means for detecting consumption of brine in regenerating operation.
An invention according to a fourth aspect is characterized in that a branching portion for branching feedwater to each of the water softeners is provided on a feedwater line to each of the water softeners, and joint means for joining treated water from each of the water softeners is provided, the joint means being connected to a treated water line.
An invention according to a fifth aspect is characterized in that the inlet hardness measurement means is provided upstream to the branching portion and the treated water quantity measurement means is provided downstream from the joint means.
An invention according to a sixth aspect is characterized in that the hardness leakage detection mean for measuring hardness of treated water after passing through the water softener and detecting hardness leakage is provided downstream from the joint means.
An invention according to a seventh aspect includes a singularity of brine tank, the brine tank being connected to each of the water softeners in a switchable way via switching means provided on a brine line, the brine concentration detection means being provided upstream to the switching means.
An invention according to an eighth aspect is characterized in that the brine consumption detection means is provided on the brine tank.
An invention according to a ninth aspect is composed of the steps of setting in advance a setting value of a hardness removal amount till a next regenerating operation based on brine concentration in regenerating operation and brine consumption in regenerating operation; obtaining an integrated value of a hardness removal amount with lapse of time based on inlet hardness and a quantity of treated water, and commencing regenerating operation when the integrated value reaches the setting value.
An invention according to a tenth aspect is characterized in that when hardness of treated water after passing through the water softener is measured and hardness leakage is detected, regenerating operation is commenced immediately.
Description will now be given of the embodiment of the present invention. The invention is applicable to a water softening device composed of a means for measuring the hardness of feedwater to a water softener on an inlet side of the water softener, a means for measuring the flow rate of treated water after passing through the water softener, a means for detecting the concentration of brine in regenerating operation, a means for detecting the consumption of brine in regenerating operation, and a control unit for controlling regenerating operation of the water softener based on the detected value by the inlet hardness measurement means, the flow rate of treated water, the brine concentration in regenerating operation, and the brine consumption in regenerating operation.
The water softening device is basically made up of a resin tank filled with ion exchange resin and a control valve. The control valve is connected to a feedwater line to feed water to the resin tank and a treated water line to feed softened water to a soft water tank. The control valve is connected to a brine tank via a brine line as well as to a drain line. The feedwater line is provided with an inlet hardness measurement means as a hardness detection means for measuring the hardness of feedwater, the treated water line is provided with a treated water quantity measurement means and a hardness leakage detection means, the brine line is provided with a brine concentration detection means, and the brine tank is provided with the brine consumption detection means. Further, the inlet hardness measurement means, the control valve, the treated water quantity measurement means, the hardness leakage detection means, the brine concentration detection means, and the brine consumption detection means are each connected to a control unit via a signal line.
For supporting continuous supply of treated water for over 24 hours, there is a configuration of disposing a plurality of water softening devices in parallel. Basically in this configuration, a plurality of the water softening devices, each composed of the inlet hardness measurement means, the control valve, the treated water quantity measurement means, the brine concentration detection means, and the brine consumption detection means, are disposed in parallel. Each of the water softening devices is connected in a switchable way so as to independently perform such operation as water flowing operation and regenerating operation. More particularly, between the feedwater line and the treated water line, a plurality of water softening devices, each having an independent water softening function, are connected in parallel in a switchable way. This enables the water softening devices to be switched to such operation state as a water flowing state, a regenerating state, and a standby state, resulting in supporting continuous supply of treated water for over 24 hours.
In the configuration of disposing a plurality of the water softening devices in parallel, among the components composing each of the water softening devices, the sharable components are connected so as to be sharable.
In disposing the inlet hardness measurement means, a branching portion for branching the feedwater line is provided on the feedwater line to feed feedwater to each of the water softening devices, and the inlet hardness measurement means is provided upstream to the branching portion. Consequently, the inlet hardness of feedwater to each of the water softening devices may be detected with one measurement means.
In disposing the brine concentration detection means, a singularity of brine tank and each of the water softening devices are connected via a brine line, on which a switching means for switching brine feed to each of the water softening devices is provided, and a singularity of the brine concentration detection means is provided upstream to the switching means. Consequently, brine concentration in each of the water softening devices in regenerating operation may be separately detected with one detection means. Here, the brine concentration detection means may be provided not only on the brine line but also on the brine tank. More specifically, as long as the brine concentration detection means is provided upstream to the switching means, it may be provided not only on the brine line but also on the brine tank.
In disposing the brine consumption detection means, the brine consumption detection means is provided on a singularity of the brine tank. Consequently, brine consumption in each of the water softening devices in regenerating operation may be separately detected with one detection means.
In disposing the treated water quantity measurement means, a joint means for joining treated water from each of the water softening devices is provided on the treated water line, and the treated water quantity measurement means is provided downstream from the joint means. Consequently, the quantity of treated water in water flowing operation in each of the water softening devices may be separately detected with one measurement means.
Further, in the configuration of disposing a plurality of the water softening devices in parallel, a hardness leakage detection means for measuring the hardness of treated water and detecting hardness leakage may be provided. In this case, the hardness leakage detection means may be provided separately on each treated water line in each of the water softening devices or a singularity of the hardness leakage detection means may be provided downstream from the joint means. In the latter configuration, the hardness leakage during water flowing operation in each of the water softening devices may be detected separately with one detection means.
Description will now be given of a control method of the above-configured water softening device. The control method in the present invention includes the steps of obtaining the setting value of a hardness removal amount till a next regenerating operation based on brine concentration in regenerating operation and brine consumption in regenerating operation, obtaining an integrated value of the hardness removal amount with lapse of time based on a detected value by the inlet hardness measurement means provided on the feedwater line for feeding water and a detected value by a flow rate detection means for detecting the flow rate of softened water, and commencing regenerating operation of a water softener when the integrated value becomes equal to the setting value. More particularly, when an exchange ability of ion exchange resin filled in the resin tank of the water softener (after regeneration, the regeneration degree is determined by the concentration of brine in regenerating operation and the exchange ability of ion exchange resin is uniformly determined by the regeneration degree and consumption of salt) becomes almost equal to an integrated hardness removal amount obtained by the hardness measured by the inlet hardness measurement means and the flow rate measured by the flow rate detection means (i.e. an exchange amount of ion exchange resin that performed ion exchange), notification is sent to a control unit and regenerating operation is thereby commenced.
Also in the configuration of disposing a hardness leakage detection means on the treated water line, if ion exchange resin reaches a treatment limit earlier than expected due to deterioration of the ion exchange resin and the like and thereby causes hardness leakage, the hardness leakage detection means detects the leakage and reports it to the control unit for immediately commencing regenerating operation.
As described above, the water softening device and the method for regeneration control thereof according to the present invention enables efficient regeneration of ion exchange resin and further implements reliable and proper regeneration.